The Dupont isolator system is a lysis-centrifugation blood culture system which has been found by some investigators to yield more rapid results as well as to have greater sensitivity for detection of yeast and staphylococci in blood. There has been some variability in the results reported by different investigators, but the major findings so far suggest that lysiscentrifugation may be superior to routine methods for at least certain organisms. Three patient-care services of the Clinical Center (2 oncology and 1 intensive care) are cooperating in an evaluation of the Isolator technique for blood cultures drawn on their patients. Blood specimens for culture are simultaneously being drawn into one routine blood culture bottle and one isolator tube. Information as to the type of organisms isolated, time to detection of a positive culture, and time to obtain growth for susceptibility testing and identification will be compiled and analyzed after 200 significant positive cultures are obtained.